A collection of devices intended to be used for the purpose of dehumidifying exhaled gas prior to its analysis in a gas analyser. It is composed of a length of hollow tubing made from one of several malleable or semi-rigid materials (e.g., silicone, plastic, rubber or nylon) and an integrated filter which absorbs (subtracts) the humidity from the gases before they enter the analysing chamber of the parent device. It has a limited lifetime and may be exchanged by the user, in which case it will typically be located on the outside of the parent device. This is a single-use device.